The biological measures core will provide support for the scientific projects in three main areas - (1) MRI and microPET imaging of study subjects, (2) data collection and analysis methods neuroendocrine (hormonal) measures obtained from study subjects, and (3) data collection and analysis methods for psychophysiological measures on study subjects. The core will be responsible for maintaining protocols, hardware and analysis methods that are necessary for the projects. The core will also provide training to project staff in data acquisition and analysis methods in each of the three domains (neuroimaging, neuroendocrine and psychophysiological measures). Regular quality assurance programs will be implemented. In addition, the imaging portion of the core will be responsible for developing new image acquisition and image analysis methods that will improve the imaging sensitivity, decrease image artifacts (distortion and localized signal loss in functional MRI scans), and improve animal imaging methods for both MRI and microPET.